In this paper,the Graphics Processing Unit-based match and locate(GPU-M&L)and double-difference(DD)location algorithm are used to analyze the 10-year continuous seismic data from 2009 to 2018 recorded by 18 stations in Yancheng and its adjacent areas. Firstly,211 seismic events are selected from the network catalog as template events,and then the GPU-M&L is used to detect and identify the earthquakes near Yancheng,Jiangsu Province. A total of 1349 seismic events are identified,which is about 3 times of the network catalog. The nominal magnitude of completeness is reduced from M_L1.9 given by the network catalog to M_L1.2 given in this study. Then we use the double-difference location algorithm to precisely locate the detected seismic events,and our relocation results show that the seismic intensive zone in Jianhu area is related to Hongze-goudun fault,the dominant distribution of focal depth is 5~20km,the focal depth on both sides of the fault zone has significant difference,the fault zone inclines to northwest;the focal depth of Sheyang earthquake swarm is deeper than Jianhu earthquake swarm,the dominant distribution is 10~25km,and the focal depth gradually becomes shallower from southeast to northwest;Baoying earthquake cluster may be related to Yancheng-Nanyang coast fault. Since there are relatively few template events in Dongtai area,the seismic events are scattered around the Chenjiabao-xiaohai fault zone after scanning and positioning. The results of this paper provide important basic data support for the study of seismicity and deep structure of seismogenic fault in Yancheng area.